Title 24 Reports in Mendocino County

An exact half each

We derive 26 ZIP codes for Mendocino County, and they divide precisely: thirteen in zone 1 and thirteen in zone 2. The reason is visible on any road map: the county is two parallel strips running north to south, the coast and the inland valleys, with a ridge of forest between them.

The coast road

Highway 1 is zone 1 from one end of the county to the other. Anchor Bay sits near the southern end; Point Arena and Manchester follow. Albion, Little River, Mendocino and Caspar lie in the middle stretch, with Fort Bragg and Cleone to the north. Every coastal ZIP code we derive carries the same assignment.

The valley road

US 101 runs through zone 2: Hopland, then Ukiah with Calpella and Redwood Valley just north of it, then Willits and Brooktrails, then Laytonville. The side valleys reached from it are zone 2 as well — Covelo in Round Valley, plus Boonville and Philo in the Anderson Valley on Highway 128.

Where the pattern slips

The two-road rule fails at the edges, and that is where a check earns its keep. Leggett, where Highway 1 ends at US 101, is zone 1 although it sits on the inland highway; Laytonville, further south on 101, is zone 2. Comptche, well inland from the town of Mendocino, is zone 1 too. Being off the coast is not the same thing as being in zone 2.

Four cities, two on each side

The county's four incorporated cities on the Department of Finance's 2026 estimates follow the same divide. Fort Bragg and Point Arena are zone 1 coastal cities; Ukiah and Willits are zone 2. Inside any of the four, the city permits the work; everywhere else the county does, and the county's own territory runs through both zones. Which office reviews a project says nothing about which targets it must meet.

Every ZIP code by zone

Zones per the Energy Commission; county membership and community names per the 2020 Census.

• Climate zone 1 — 95410 (Albion); 95417; 95420 (Caspar); 95427 (Comptche); 95432; 95437 (Fort Bragg, Cleone); 95445 (Anchor Bay); 95456 (Little River); 95459 (Manchester); 95460 (Mendocino, Caspar); 95468 (Point Arena); 95488; 95585 (Leggett)
• Climate zone 2 — 95415 (Boonville); 95428 (Covelo); 95429; 95449 (Hopland); 95454 (Laytonville); 95463; 95466 (Philo); 95470 (Redwood Valley); 95482 (Ukiah, Talmage, Calpella); 95490 (Willits, Brooktrails); 95494; 95587; also 95469, split with a neighbouring county (below)

A ZIP code that crosses the county line

• 95469 (Potter Valley) — about 63% within Mendocino County, the remainder in Lake 37%

Potter Valley's ZIP code reaches east into Lake County. It is zone 2 on both sides, because the zone follows the ZIP code rather than the county; what the line decides is whether Mendocino or Lake County issues the permit.

Finding the zone for your own project

The zone is set by the project's location and confirmed from the ZIP code against the Energy Commission's published table — not from the county name and not from the nearest large town. Because Mendocino County contains more than one zone, that check decides which set of numbers a report is written against.

Give us the project address and we determine the zone as part of preparing the report. It is the first thing established, because every insulation, glazing and equipment figure downstream depends on it.

Climate zones in Mendocino County

Mendocino County contains California climate zones 1 and 2. The zone drives the insulation, glazing and equipment performance a report has to demonstrate, and it is confirmed from the project ZIP code against the Energy Commission's published table.